Yeast Mannans and Stool Frequency

April 14, 2026 updated by: University of Florida

Efficacy of Yeast Mannan Supplementation on Increasing Stool Frequency in Generally Healthy Adults: A Randomized Controlled Trial

Findings from an open-label pilot study of 20 adults suggested that supplementation with 15 g/day of yeast mannans was highly tolerable and demonstrated specific modulation of the microbiota and increased stool frequency in a subset of subjects reporting ≤1 stool per day at baseline. The primary aim of this randomized, double-blind, controlled trial is to determine if yeast mannan supplementation at 12 g/day will increase stool frequency in generally healthy adults reporting ≤1 stool per day. Secondary aims will determine the effect of yeast mannans on intestinal transit time, gastrointestinal symptoms, fecal microbiota composition, and urinary and fecal metabolomics.

Study Overview

Status

Active, not recruiting

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Estimated)

70

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • United States
    • Florida
      • Gainesville, Florida, United States, 32611
        • Department of Food Science and Human Nutrition

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

  • Adults who report a stool frequency of ≤ 1 per day.
  • Able to provide written informed consent in English.
  • Willingness to consume 1 supplement (12 g of yeast mannans or control) daily for 28 days.
  • Willingness to maintain their usual diet and physical activity patterns throughout the study and refrain from the consumption of any yeast-based foods (e.g. Marmite or Vegemite) or yeast extract supplements.
  • Willing to comply with study procedures, including stool and urine colle

Exclusion Criteria:

  • Stool frequency of < 3 per week
  • Yeast allergy
  • Vegan dietary pattern
  • Self-reported kidney disease
  • Elite athletes or long-distance runners
  • Use of antibiotic drugs within 1 month of screening
  • Current use of laxatives or antidiarrheal medications
  • Use of other investigational products within 3 months of the screening
  • Previously or currently being treated for intestinal diseases or conditions, including irritable bowel disease (i.e., IBS-D or IBS-mixed), Crohn's disease, ulcerative colitis, celiac disease, or gastrointestinal cancer.
  • Previous gastrointestinal surgery (e.g., gastric bypass, fundoplication, bowel resection).
  • Current cancer treatment.
  • Currently pregnant.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Other
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Triple

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Yeast mannan supplementation
Yeast cell wall fraction obtained from Saccharomyces cerevisiae containing mannan-oligosaccharides and mannoproteins will be supplemented at 12 g/day.
Dietary supplement: Yeast mannan
Yeast cell wall fraction of manno-oligosaccharides and mannoproteins supplemented at 12 g/day.
Other Names:
  • yeast cell wall fraction
Placebo Comparator: Control supplementation
The control supplement, containing yeast protein, yeast extract, and maltodextrin, will be provided at 12 g/day.
Dietary supplement: Control (placebo)
A supplement containing yeast protein, yeast extract, and maltodextrin, provided at 12 g/day.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Defecation frequency
Time Frame: From enrollment to the end of treatment at 6 weeks.
Mean daily defecation frequency
From enrollment to the end of treatment at 6 weeks.

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

University of Florida

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

July 17, 2025

Primary Completion (Actual)

March 16, 2026

Study Completion (Estimated)

December 31, 2026

Study Registration Dates

First Submitted

March 28, 2025

First Submitted That Met QC Criteria

April 3, 2025

First Posted (Actual)

April 4, 2025

Study Record Updates

Last Update Posted (Actual)

April 15, 2026

Last Update Submitted That Met QC Criteria

April 14, 2026

Last Verified

August 1, 2025

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • IRB202500359

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

UNDECIDED

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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